Robust passive range estimation using the waveguide invariant.

Area of Science:

• Ocean acoustics
• Acoustic signal processing
• Waveguide theory

Background:

• Estimating acoustic source range in shallow-water environments presents challenges due to complex sound propagation.
• Traditional methods often require detailed environmental knowledge or multiple receivers.
• A single-receiver approach offers a simpler, more adaptable solution.

Purpose of the Study:

• To develop and validate a range estimation algorithm for broadband acoustic sources in shallow-water waveguides.
• To utilize the waveguide invariant principle for improved acoustic source localization.
• To enhance signal-to-noise ratio without extensive environmental parameterization.

Main Methods:

• Application of the waveguide invariant principle for acoustic source range estimation.
• Development of a relationship between signal processing and ocean-acoustic parameters.
• Heuristic determination of minimum source bandwidth and horizontal aperture requirements.
• Testing the algorithm on experimental and simulated data.

Main Results:

• The developed algorithm accurately estimates acoustic source range using a single towed receiver.
• The method effectively increases signal-to-noise ratio by leveraging signal processing and environmental parameter relationships.
• The algorithm demonstrated accuracy within approximately 25% for tested ranges (500-2200 m) and frequencies (350-700 Hz).

Conclusions:

• The waveguide invariant principle provides a robust method for acoustic source range estimation in shallow water.
• The developed algorithm offers a practical solution requiring minimal a priori environmental knowledge.
• This approach is effective for broadband acoustic sources and can be implemented with a single receiver.